Direct and indirect regulation of Pom1 cell size pathway by the protein phosphatase 2C Ptc1

The fission yeast cells Schizosaccharomyces pombe divide at constant cell size regulated by environmental stimuli. An important pathway of cell size control involves the membrane-associated DYRK-family kinase Pom1, which forms decreasing concentration gradients from cell poles and inhibits mitotic inducers at mid-cell. Here, we identify the phosphatase 2C Ptc1 as negative regulator of Pom1. Ptc1 localizes to cell poles in a manner dependent on polarity and cell-wall integrity factors. We show that Ptc1 directly binds Pom1 and can dephosphorylate it in vitro but modulates Pom1 localization indirectly upon growth in low glucose conditions by influencing microtubule stability. Thus, Ptc1 phosphatase plays both direct and indirect roles in the Pom1 cell size control pathway. [Media: see text]

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Direct and indirect regulation of Pom1 cell size pathway by the protein phosphatase 2C Ptc1

10.1101/2020.06.03.131227 ◽

2020 ◽

Author(s):

Veneta Gerganova ◽

Payal Bhatia ◽

Sophie G Martin

Keyword(s):

Cell Size ◽

Size Control ◽

Negative Regulator ◽

Yeast Cells ◽

Concentration Gradients ◽

Important Pathway ◽

Low Glucose ◽

Constant Cell ◽

Cell Size Control

AbstractThe fission yeast cells Schizosaccharomyces pombe divide at constant cell size regulated by environmental stimuli. An important pathway of cell size control involves the membrane-associated DYRK-family kinase Pom1, which forms decreasing concentration gradients from cell poles and inhibits mitotic inducers at mid-cell. Here, we identify the phosphatase 2C Ptc1 as negative regulator of Pom1. Ptc1 localizes to cell poles in a manner dependent on polarity and cell-wall integrity factors. We show that Ptc1 directly binds Pom1 and can dephosphorylate it in vitro but modulates Pom1 localization indirectly upon growth in low glucose conditions by influencing microtubule stability. Thus, Ptc1 phosphatase plays both direct and indirect roles in the Pom1 cell size control pathway.

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Cell Size Control in Plants

Annual Review of Genetics ◽

10.1146/annurev-genet-112618-043602 ◽

2019 ◽

Vol 53 (1) ◽

pp. 45-65 ◽

Cited By ~ 3

Author(s):

Marco D'Ario ◽

Robert Sablowski

Keyword(s):

Cell Size ◽

Mammalian Cells ◽

Molecular Mechanisms ◽

Growth Control ◽

Size Control ◽

Yeast Cells ◽

Shoot Meristem ◽

Functional Consequences ◽

Cell Size Control ◽

Size Heterogeneity

The genetic control of the characteristic cell sizes of different species and tissues is a long-standing enigma. Plants are convenient for studying this question in a multicellular context, as their cells do not move and are easily tracked and measured from organ initiation in the meristems to subsequent morphogenesis and differentiation. In this article, we discuss cell size control in plants compared with other organisms. As seen from yeast cells to mammalian cells, size homeostasis is maintained cell autonomously in the shoot meristem. In developing organs, vacuolization contributes to cell size heterogeneity and may resolve conflicts between growth control at the cellular and organ levels. Molecular mechanisms for cell size control have implications for how cell size responds to changes in ploidy, which are particularly important in plant development and evolution. We also discuss comparatively the functional consequences of cell size and their potential repercussions at higher scales, including genome evolution.

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